Source code for stable_baselines.a2c.a2c

import time
from collections import deque

import gym
import numpy as np
import tensorflow as tf

from stable_baselines import logger
from stable_baselines.common import explained_variance, tf_util, ActorCriticRLModel, SetVerbosity, TensorboardWriter
from stable_baselines.common.policies import LstmPolicy, ActorCriticPolicy
from stable_baselines.common.runners import AbstractEnvRunner
from stable_baselines.a2c.utils import discount_with_dones, Scheduler, find_trainable_variables, mse, \
from stable_baselines.ppo2.ppo2 import safe_mean

[docs]class A2C(ActorCriticRLModel): """ The A2C (Advantage Actor Critic) model class, :param policy: (ActorCriticPolicy or str) The policy model to use (MlpPolicy, CnnPolicy, CnnLstmPolicy, ...) :param env: (Gym environment or str) The environment to learn from (if registered in Gym, can be str) :param gamma: (float) Discount factor :param n_steps: (int) The number of steps to run for each environment per update (i.e. batch size is n_steps * n_env where n_env is number of environment copies running in parallel) :param vf_coef: (float) Value function coefficient for the loss calculation :param ent_coef: (float) Entropy coefficient for the loss caculation :param max_grad_norm: (float) The maximum value for the gradient clipping :param learning_rate: (float) The learning rate :param alpha: (float) RMSProp decay parameter (default: 0.99) :param epsilon: (float) RMSProp epsilon (stabilizes square root computation in denominator of RMSProp update) (default: 1e-5) :param lr_schedule: (str) The type of scheduler for the learning rate update ('linear', 'constant', 'double_linear_con', 'middle_drop' or 'double_middle_drop') :param verbose: (int) the verbosity level: 0 none, 1 training information, 2 tensorflow debug :param tensorboard_log: (str) the log location for tensorboard (if None, no logging) :param _init_setup_model: (bool) Whether or not to build the network at the creation of the instance (used only for loading) :param policy_kwargs: (dict) additional arguments to be passed to the policy on creation :param full_tensorboard_log: (bool) enable additional logging when using tensorboard WARNING: this logging can take a lot of space quickly """ def __init__(self, policy, env, gamma=0.99, n_steps=5, vf_coef=0.25, ent_coef=0.01, max_grad_norm=0.5, learning_rate=7e-4, alpha=0.99, epsilon=1e-5, lr_schedule='constant', verbose=0, tensorboard_log=None, _init_setup_model=True, policy_kwargs=None, full_tensorboard_log=False): super(A2C, self).__init__(policy=policy, env=env, verbose=verbose, requires_vec_env=True, _init_setup_model=_init_setup_model, policy_kwargs=policy_kwargs) self.n_steps = n_steps self.gamma = gamma self.vf_coef = vf_coef self.ent_coef = ent_coef self.max_grad_norm = max_grad_norm self.alpha = alpha self.epsilon = epsilon self.lr_schedule = lr_schedule self.learning_rate = learning_rate self.tensorboard_log = tensorboard_log self.full_tensorboard_log = full_tensorboard_log self.graph = None self.sess = None self.learning_rate_ph = None self.n_batch = None self.actions_ph = None self.advs_ph = None self.rewards_ph = None self.pg_loss = None self.vf_loss = None self.entropy = None self.params = None self.apply_backprop = None self.train_model = None self.step_model = None self.step = None self.proba_step = None self.value = None self.initial_state = None self.learning_rate_schedule = None self.summary = None self.episode_reward = None # if we are loading, it is possible the environment is not known, however the obs and action space are known if _init_setup_model: self.setup_model() def _get_pretrain_placeholders(self): policy = self.train_model if isinstance(self.action_space, gym.spaces.Discrete): return policy.obs_ph, self.actions_ph, policy.policy return policy.obs_ph, self.actions_ph, policy.deterministic_action
[docs] def setup_model(self): with SetVerbosity(self.verbose): assert issubclass(self.policy, ActorCriticPolicy), "Error: the input policy for the A2C model must be an " \ "instance of common.policies.ActorCriticPolicy." self.graph = tf.Graph() with self.graph.as_default(): self.sess = tf_util.make_session(graph=self.graph) self.n_batch = self.n_envs * self.n_steps n_batch_step = None n_batch_train = None if issubclass(self.policy, LstmPolicy): n_batch_step = self.n_envs n_batch_train = self.n_envs * self.n_steps step_model = self.policy(self.sess, self.observation_space, self.action_space, self.n_envs, 1, n_batch_step, reuse=False, **self.policy_kwargs) with tf.variable_scope("train_model", reuse=True, custom_getter=tf_util.outer_scope_getter("train_model")): train_model = self.policy(self.sess, self.observation_space, self.action_space, self.n_envs, self.n_steps, n_batch_train, reuse=True, **self.policy_kwargs) with tf.variable_scope("loss", reuse=False): self.actions_ph = train_model.pdtype.sample_placeholder([None], name="action_ph") self.advs_ph = tf.placeholder(tf.float32, [None], name="advs_ph") self.rewards_ph = tf.placeholder(tf.float32, [None], name="rewards_ph") self.learning_rate_ph = tf.placeholder(tf.float32, [], name="learning_rate_ph") neglogpac = train_model.proba_distribution.neglogp(self.actions_ph) self.entropy = tf.reduce_mean(train_model.proba_distribution.entropy()) self.pg_loss = tf.reduce_mean(self.advs_ph * neglogpac) self.vf_loss = mse(tf.squeeze(train_model._value), self.rewards_ph) loss = self.pg_loss - self.entropy * self.ent_coef + self.vf_loss * self.vf_coef tf.summary.scalar('entropy_loss', self.entropy) tf.summary.scalar('policy_gradient_loss', self.pg_loss) tf.summary.scalar('value_function_loss', self.vf_loss) tf.summary.scalar('loss', loss) self.params = find_trainable_variables("model") grads = tf.gradients(loss, self.params) if self.max_grad_norm is not None: grads, _ = tf.clip_by_global_norm(grads, self.max_grad_norm) grads = list(zip(grads, self.params)) with tf.variable_scope("input_info", reuse=False): tf.summary.scalar('discounted_rewards', tf.reduce_mean(self.rewards_ph)) tf.summary.scalar('learning_rate', tf.reduce_mean(self.learning_rate)) tf.summary.scalar('advantage', tf.reduce_mean(self.advs_ph)) if self.full_tensorboard_log: tf.summary.histogram('discounted_rewards', self.rewards_ph) tf.summary.histogram('learning_rate', self.learning_rate) tf.summary.histogram('advantage', self.advs_ph) if tf_util.is_image(self.observation_space): tf.summary.image('observation', train_model.obs_ph) else: tf.summary.histogram('observation', train_model.obs_ph) trainer = tf.train.RMSPropOptimizer(learning_rate=self.learning_rate_ph, decay=self.alpha, epsilon=self.epsilon) self.apply_backprop = trainer.apply_gradients(grads) self.train_model = train_model self.step_model = step_model self.step = step_model.step self.proba_step = step_model.proba_step self.value = step_model.value self.initial_state = step_model.initial_state tf.global_variables_initializer().run(session=self.sess) self.summary = tf.summary.merge_all()
def _train_step(self, obs, states, rewards, masks, actions, values, update, writer=None): """ applies a training step to the model :param obs: ([float]) The input observations :param states: ([float]) The states (used for recurrent policies) :param rewards: ([float]) The rewards from the environment :param masks: ([bool]) Whether or not the episode is over (used for recurrent policies) :param actions: ([float]) The actions taken :param values: ([float]) The logits values :param update: (int) the current step iteration :param writer: (TensorFlow Summary.writer) the writer for tensorboard :return: (float, float, float) policy loss, value loss, policy entropy """ advs = rewards - values cur_lr = None for _ in range(len(obs)): cur_lr = self.learning_rate_schedule.value() assert cur_lr is not None, "Error: the observation input array cannon be empty" td_map = {self.train_model.obs_ph: obs, self.actions_ph: actions, self.advs_ph: advs, self.rewards_ph: rewards, self.learning_rate_ph: cur_lr} if states is not None: td_map[self.train_model.states_ph] = states td_map[self.train_model.masks_ph] = masks if writer is not None: # run loss backprop with summary, but once every 10 runs save the metadata (memory, compute time, ...) if self.full_tensorboard_log and (1 + update) % 10 == 0: run_options = tf.RunOptions(trace_level=tf.RunOptions.FULL_TRACE) run_metadata = tf.RunMetadata() summary, policy_loss, value_loss, policy_entropy, _ = [self.summary, self.pg_loss, self.vf_loss, self.entropy, self.apply_backprop], td_map, options=run_options, run_metadata=run_metadata) writer.add_run_metadata(run_metadata, 'step%d' % (update * (self.n_batch + 1))) else: summary, policy_loss, value_loss, policy_entropy, _ = [self.summary, self.pg_loss, self.vf_loss, self.entropy, self.apply_backprop], td_map) writer.add_summary(summary, update * (self.n_batch + 1)) else: policy_loss, value_loss, policy_entropy, _ = [self.pg_loss, self.vf_loss, self.entropy, self.apply_backprop], td_map) return policy_loss, value_loss, policy_entropy
[docs] def learn(self, total_timesteps, callback=None, seed=None, log_interval=100, tb_log_name="A2C", reset_num_timesteps=True): new_tb_log = self._init_num_timesteps(reset_num_timesteps) with SetVerbosity(self.verbose), TensorboardWriter(self.graph, self.tensorboard_log, tb_log_name, new_tb_log) \ as writer: self._setup_learn(seed) self.learning_rate_schedule = Scheduler(initial_value=self.learning_rate, n_values=total_timesteps, schedule=self.lr_schedule) runner = A2CRunner(self.env, self, n_steps=self.n_steps, gamma=self.gamma) self.episode_reward = np.zeros((self.n_envs,)) # Training stats (when using Monitor wrapper) ep_info_buf = deque(maxlen=100) t_start = time.time() for update in range(1, total_timesteps // self.n_batch + 1): # true_reward is the reward without discount obs, states, rewards, masks, actions, values, ep_infos, true_reward = ep_info_buf.extend(ep_infos) _, value_loss, policy_entropy = self._train_step(obs, states, rewards, masks, actions, values, self.num_timesteps // (self.n_batch + 1), writer) n_seconds = time.time() - t_start fps = int((update * self.n_batch) / n_seconds) if writer is not None: self.episode_reward = total_episode_reward_logger(self.episode_reward, true_reward.reshape((self.n_envs, self.n_steps)), masks.reshape((self.n_envs, self.n_steps)), writer, self.num_timesteps) self.num_timesteps += self.n_batch + 1 if callback is not None: # Only stop training if return value is False, not when it is None. This is for backwards # compatibility with callbacks that have no return statement. if callback(locals(), globals()) is False: break if self.verbose >= 1 and (update % log_interval == 0 or update == 1): explained_var = explained_variance(values, rewards) logger.record_tabular("nupdates", update) logger.record_tabular("total_timesteps", self.num_timesteps) logger.record_tabular("fps", fps) logger.record_tabular("policy_entropy", float(policy_entropy)) logger.record_tabular("value_loss", float(value_loss)) logger.record_tabular("explained_variance", float(explained_var)) if len(ep_info_buf) > 0 and len(ep_info_buf[0]) > 0: logger.logkv('ep_reward_mean', safe_mean([ep_info['r'] for ep_info in ep_info_buf])) logger.logkv('ep_len_mean', safe_mean([ep_info['l'] for ep_info in ep_info_buf])) logger.dump_tabular() return self
[docs] def save(self, save_path): data = { "gamma": self.gamma, "n_steps": self.n_steps, "vf_coef": self.vf_coef, "ent_coef": self.ent_coef, "max_grad_norm": self.max_grad_norm, "learning_rate": self.learning_rate, "alpha": self.alpha, "epsilon": self.epsilon, "lr_schedule": self.lr_schedule, "verbose": self.verbose, "policy": self.policy, "observation_space": self.observation_space, "action_space": self.action_space, "n_envs": self.n_envs, "_vectorize_action": self._vectorize_action, "policy_kwargs": self.policy_kwargs } params = self._save_to_file(save_path, data=data, params=params)
class A2CRunner(AbstractEnvRunner): def __init__(self, env, model, n_steps=5, gamma=0.99): """ A runner to learn the policy of an environment for an a2c model :param env: (Gym environment) The environment to learn from :param model: (Model) The model to learn :param n_steps: (int) The number of steps to run for each environment :param gamma: (float) Discount factor """ super(A2CRunner, self).__init__(env=env, model=model, n_steps=n_steps) self.gamma = gamma def run(self): """ Run a learning step of the model :return: ([float], [float], [float], [bool], [float], [float]) observations, states, rewards, masks, actions, values """ mb_obs, mb_rewards, mb_actions, mb_values, mb_dones = [], [], [], [], [] mb_states = self.states ep_infos = [] for _ in range(self.n_steps): actions, values, states, _ = self.model.step(self.obs, self.states, self.dones) mb_obs.append(np.copy(self.obs)) mb_actions.append(actions) mb_values.append(values) mb_dones.append(self.dones) clipped_actions = actions # Clip the actions to avoid out of bound error if isinstance(self.env.action_space, gym.spaces.Box): clipped_actions = np.clip(actions, self.env.action_space.low, self.env.action_space.high) obs, rewards, dones, infos = self.env.step(clipped_actions) for info in infos: maybe_ep_info = info.get('episode') if maybe_ep_info is not None: ep_infos.append(maybe_ep_info) self.states = states self.dones = dones self.obs = obs mb_rewards.append(rewards) mb_dones.append(self.dones) # batch of steps to batch of rollouts mb_obs = np.asarray(mb_obs, dtype=self.obs.dtype).swapaxes(1, 0).reshape(self.batch_ob_shape) mb_rewards = np.asarray(mb_rewards, dtype=np.float32).swapaxes(0, 1) mb_actions = np.asarray(mb_actions, dtype=self.env.action_space.dtype).swapaxes(0, 1) mb_values = np.asarray(mb_values, dtype=np.float32).swapaxes(0, 1) mb_dones = np.asarray(mb_dones, dtype=np.bool).swapaxes(0, 1) mb_masks = mb_dones[:, :-1] mb_dones = mb_dones[:, 1:] true_rewards = np.copy(mb_rewards) last_values = self.model.value(self.obs, self.states, self.dones).tolist() # discount/bootstrap off value fn for n, (rewards, dones, value) in enumerate(zip(mb_rewards, mb_dones, last_values)): rewards = rewards.tolist() dones = dones.tolist() if dones[-1] == 0: rewards = discount_with_dones(rewards + [value], dones + [0], self.gamma)[:-1] else: rewards = discount_with_dones(rewards, dones, self.gamma) mb_rewards[n] = rewards # convert from [n_env, n_steps, ...] to [n_steps * n_env, ...] mb_rewards = mb_rewards.reshape(-1, *mb_rewards.shape[2:]) mb_actions = mb_actions.reshape(-1, *mb_actions.shape[2:]) mb_values = mb_values.reshape(-1, *mb_values.shape[2:]) mb_masks = mb_masks.reshape(-1, *mb_masks.shape[2:]) true_rewards = true_rewards.reshape(-1, *true_rewards.shape[2:]) return mb_obs, mb_states, mb_rewards, mb_masks, mb_actions, mb_values, ep_infos, true_rewards